Short-circuiting device for motors



May 21,1929. G, L N

SHORTICIHCUITING DEVICE FOR MOTORS Filed Nov. 2, 1925 //V VE N TOR.GEORGE H. LELAND.

Patented May '21, 1929.

UNITED STATES 1,713,610 PATENT OFFICE.

GEORGE .H. LELAND, OF DAYTON, OHIO, ASSIGNOB TO THE LELAND ELECTRIC COM-iPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

SHORT-OIRCUITING DEVICE FOR MOTORS.

' Application filed No'vember 2, 1925. Serial No. 66,213.

This invention relates to short circuiting device for motors. Electricmotors of the type known as repulsion induction motors are soconstructed that the will start as repulsion motors and after t ey haveattained a predetermined speed will be automatically converted intoinduction motors. This is usually accomplished by means of a series ofweights or contact members arranged circumferentially of the axis of thecommutator and movable by centrifugal force into short circuitingcontact with the commutator bars, a

yieldable member acting on the weights tomeans for so applying anannular contractile" band to the weights that the band will cause thecontact portions of the weight to press firmly against the face of thecommutator at all times.

Other objects of the invention will appear 'as the device is describedin detail.

In the accompanying drawings Fig. 1 is 3 an end elevation, partly brokenaway, of a short circuiting device embodying my invention; Fig. 2 is alongitudinal sectional view taken centrally through such a shortcircuiting device and the commutator, show- 133 ing the weights in theirretracted positions; Fig. 3 is a similar View showing the weights intheir extended positions; Fig. 4 is a sectional view showing a slightlymodified for of my invention applied to a commutator and 40 Fig. 5 is asimilar view showing a further modification of the invention. In thesedrawings I have illustrated certain embodiments of the invention but itwill be understood that these have been chosen for i the purposes ofillustration only and that the device may take various forms withoutdeparting from the spirit of the invention.

As here shown, the short circuiting device isiapplied to a commutatorcomprising a body 7 portion 1 which is rigidly mounted on an armatureshaft 2 and is provided with the usual circumferential series ofcommutator bars 3. Mounted on this shaft 2 and spaced some dis tancefrom the face of the commutator is a retaining plate or disk 4. Thisdisk may be a band prevents any material sliding moveloosely mounted onthe shaft so that it'is capable of both rotary and axial movement withrelation thereto but its movement away from the face of the commutatoris positively limited by a stop, such as a split ring 5 seated in acircumferential groove 6 in the shaft 2. Arranged between the disk 4 andthe face of the commutator is an annular series of contact members orweights 7 which extend circumferentially of the shaft 2 and which areslidably mounted so that they may be moved outwardly by centrifugalforce to cause the contact portions 8 at the outer ends thereof to bebrought into short circuiting contact with the commutator bars 3, shownin Fig. 3. These weights may be of any suitable character and shape.Preferably they are tapered toward the axis of the shaft so as toprovide flat surfaces between adjacent weights. A yieldable device isapplied to the weights to resist their outward movement and the weightsare preferably so constructed that this yieldable device will not onlyresist the outward movement thereof but will also cause the contactportions 8 thereof to be pressed firmly against the face of thecommutator. The yieldable device may be of any suitable character but -Iprefer that it should be in the form of a contractile hand because theelasticity of such m'ent of the same relatively to the weights andthereby minimizes the friction. As here shown, this contractile band isin the form of an endless helical spring 9. Each of the weights has aportion of its forward edge, that is the edge opposite the commutator,arranged to engage and fulcrum on the retaining disk 4 and, as hereshown, the inner portions of the forward edges of the weights extendoutwardly and rearwardly so as to provide slidable fulcrum points nearthe inner ends of the'weights. The outer portions of these forward edgesof the weights extend. forwardly beyond the fulcrum point to formshoulders 10 which overhang the peripheral 100 edge of the disk 4; andconstitute stops to limit the inward movement of "the weights. The

'contractile bandis so applied to the weights and the commutator. Withsuch anarrangement of the band the tendency of the same is to cause eachweight to pivot about its point of contact with the disk and thus holdthe outer contact portion thereofagainst the face of the commutator.There are various ways .in which the contractile hand may-be soconnected with the weights and in that found the device'shownin Figs. 1,2-and .3, each weight is provided at its inner end witlian arm 11 whichprojects from the rear edge of the body of theweight toward'the commutestor. In order to accommodate this arm the body l-of the commutator isrecessed in its forward face, as shown at 12, and the arms 11 extendinto this recess. Each of the arms is provided in its outer edge with ashallow re.-

cess 13 in which the annular hand 9 is seated. The recesses arepreferablyforme'd near the are provided'in their inner portions andpreferably near the inner ends thereof with-openings 18 through which acontractile hand 19- is threaded. Preferably the inner portions of theweights are widened so as to cause the annular ha'ndto engage theweights at a considerable distance in the rear of their centers ofgravity and thus the band will tend .to rotate the weights about theirfulcrum points 15 and press the contact points 17 thereof against theface of the commutator.

. Obviously, if desired, the outer-portions of and thespring.

the walls of the openin'gslS may be cut away to, facilitate theassembling of the weights In that form of the device. illustrated Fig. 5the weights are ,shown at 20 and are similar in shapeto the plates 14OfEFig. 4

' but instead of an opening through the. same their inner rear cornersare cut away to form a recess 21. A contractile band22 is arranged inrecess and is suspended from "the weights by-suitable connectingdevices,

such as 23, which are so arranged that the force-of the band will beapplied to the In that form of the device shown in Figs. 1, 2 and 3, theforward ends of the com- I mutatorbars are flush with the face of thecommutator and the contact portions of the weights move over thecommutator bars with a sliding or wiping action. Intho'sa forms of thedevice shown in Figs. 4 and '5, the

forward ends of the commutator bars overhang the face of the commutatorand are weights 'atpoints between the respective centers of gravity'andthe commutator.

provided with arcuate recesses 24 which "form the contact surfacesandwhich are vengagedby the contact points of the weightsp The contactpoints of the weights are curved to conform to the contour of thearcuate recesses 24,'so that'tlie'weights will engage the commu'tatorbarswith a butting contact'but the arrangement is such as to eliminate'the'b urning or damaging of the contact faces due to sparking, as isfully-set forthjin my co-pend- 'ing application filed April 16,1925,Serial N o. r 23,524.

While I tain embodiments of invention 1 wish it to'be' understoodthat I.do not desire to be limited to the details thereof as various modifica'tionsmay occur to a person skilled in the art. i i i Having nowdescribed invention, what I claim as new and desire to secure by LettersPatent, is:

1. In a short ircuiting' device for a commutator, a shaft on which saidcommutator is-mounted,'-a disk mounte'dmn said shaft,

spaced from said -commutator and normally.

have shown andtdescribed cer-i held against axial movement'in adirection away from said-commutatorya series of short.

circuiting weights arranged about said shaft between saiddisk and saidcommutator and capable of ra'dial sliding movementunder the influenceofcentrifugal force, each weight on said disk and having a portion of itsother edge in sliding contact with the face of said having a portion ofthat edge opposite saidcommutator arranged to fulcrum at all timescommutator, anda contractile band'acting on the several weightsat'pointsbetween their respective centers of-gravity andsaid'c'ommutator to resist their outward movement and to press saidportions thereof respectively against the face. of said commutator and,

against said disk -2. In a shortcircuiting device for a-com'- mutator, ashaft on which said commutator is mounted,a disk mounted on said shaft,spaced from said commutator and normally held' against, axial movementin a direction away from said commutator, a series of short circuitingweights arranged about said shaft between said disk and said commutatorand capable of radial sliding movement under the influence ofcentrifugal force, each weight having a portion of that edge oppositesaid commutator arranged to fulcrum. at all times on said disk andhaving a portion of its other edge in sliding contact'with the face ofsaid commutator, each weight also having a part extending mentionedparts of said weights. I I

I 3.:In a short circuiting 'device, the combination with a shaft andacommutator mounted on said shaft, comprising a circumferential seriesof bars and havin a central toward said commutator, and a contractileband supported on the last 1 recess in the face thereof, ofa dis mountedon said shaft and spaced from the face of said commutator, an annularseries of contact weights mounted between said disk and the face of,said commutator and arranged circumferentially of said shaft for slidingmovement under the influence of centrifugal force into short circuitingcontact with said bars,

each weight having a part arranged to fulcrum at 'all times on said diskand having another part extending into said recess in said commutator,and a contractile band supported by the last mentioned parts of saidweights.

4. In a short circuiting device for a com mutator, a shaft on which saidcommutator is mounted, a disk mounted on said shaft, spaced from saidcommutator and normally held against axial movement in a direction awayfrom said commutator, a series of short circuiting weights, arrangedabout said shaft between said disk and said commutator, capable ofradial sliding movement under the influence of centrifugal force andeach having a portion arranged to have short circuiting contact withsaid commutator, and a spring element acting on said weights atialltimes to press the contact portions thereof against the commutator andto press other portions thereof against said disk.

5. In a short circuiting devicefor a commutator, a shaft on which saidcommutator is mounted, a disk movably mounted on said shaft and spacedfrom said commutator, means for limiting the movement of said disk in adirection away from said commutator, a series of short circuitingweights arranged about said shaft between said disk and said commutatorand capable of radial slidin movement under the influence of centrifugedforce, each weight having a contact portion adapted to have shortcircuiting contact with the commutator and another portion to engagesaid disk, and a spring element acting on saidweights to press saidcontact portions thereof againstsaid commutator and'to press. said otherportions thereof against said disk and hold said disk against said meansfor limiting the movement thereof.

In testimony whereof, I afiix my signature hereto.

GEORGE H. LELAND.-

' CERTIFICATE OF CORRECTION.

Patent No. 1,713, 610;

Grantedhlay 21, 1929, to

GEORGE n. LELAND.

It is hereby certified that the above numbered patent was erroneouslyissued to "The Leland Electric Company,

i forest in said invention, asslgnee at the mm" H "Leland, and TheLeland Electric Company, of

said corporation as shown by the records of assignments in this Patentshould be read with this correction ther'e conform to the record of thecase in'the Patent Office.

18th day of June, A. D. 1929.

7 been issued to the inventor, said Dayton, Ohio, a corporation of Ohio,interest only in said invention, office; and that the said Lettersinthat the same may Signed and sealed this (Seal) whereas and patentshould have being assignee of one-half r M. .J'. Moore,

CERTIFICATE OF CORRECTION.

Patent No. 1,713,610. Granted May 21, 1929, to

GEORGE H. LELAND.

It is hereby certified that the above numbered patent was erroneousiyissued to "The Leiand Electric Company, of Dayton, Ohio, a corporationof Ohio", as assignee of the entire interest in said invention, whereassaid patent should have been issued to the inventor, said "Leland, andThe Leland Electric Company, of Dayton, Ohio, a corporation of Ohio",said corporation being assignee of one-half interest only in saidinvention, as shown by the records of assignments in this off ice; andthat the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 18th day of June, A. D. 1929.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

